Narrative:

After pushback at sfo, we obtained clearance from ground control to taxi to runway 10R. We arrived at runway 10R, were in first position to depart, but there remained approximately 2 mins for the necessary stabilization time on the PW4000 engines. Tower cleared us into position and hold on runway 10R and we acknowledged and advised ATC of the additional time we would require prior to being able to accept a takeoff clearance. Tower's response was to cancel clearance and to taxi over to runway 10L via taxiway right. Another aircraft was parked on taxiway south facing southeast and northwest of taxiway right. We complied with tower's instructions and upon arrival at runway 10L, were instructed to taxi into position and hold. I asked the first officer whether we were 'good to go' on runway 10L from the intersection, 2 times. The reply was 'we're good on runway 10L,' and 'we're good to go.' subsequent clearance for takeoff was SOP and uneventful. Txwys U and right at sfo's south side of runway 10L intersect the runway very close to the same point. In fact, an argument could be made that if an aircraft was instructed to taxi into position and hold on runway 10L at taxiway U and did so, the line-up distance would put the aircraft geographically very close and adjacent to taxiway right. The point, however, is this: once airborne, I went back and checked for myself whether in fact engineering numbers existed for an intersection departure from taxiway right. I learned that they did not. The safety of the takeoff was not in question at that point. I knew that plenty of runway had been available (greater than 10000 ft), takeoff data for runway 10L taxiway U was available, VFR WX conditions existed, a relatively light aircraft weight, and parallel runways in very close proximity to one another, the takeoff data of which had been just thoroughly reviewed. What did trouble me was my failure to convey to the first officer a clear and accurate inquiry regarding the 'legality' of that specific takeoff from runway 10L at taxiway right intersection. Nothing on that day would have suggested we were in a runway or performance limited situation or other unsafe condition, and therefore no obvious 'red flags' were waving before my eyes. I did even recognize and acknowledge the need to check for engineering numbers for a departure from that intersection. The breakdown occurred in communication. I have since recapped the situation many times and have recommitted myself to clrer and more accurate communication skills in the cockpit. Thankfully this was not a significant event. It was, however, a significant and valuable learning opportunity.

Related reports:

Google
 

Original NASA ASRS Text

Title: A WDB CREW, DEPARTING SFO, TOOK OFF FROM AN INTXN THEY DIDN'T HAVE THE DATA FOR.

Narrative: AFTER PUSHBACK AT SFO, WE OBTAINED CLRNC FROM GND CTL TO TAXI TO RWY 10R. WE ARRIVED AT RWY 10R, WERE IN FIRST POS TO DEPART, BUT THERE REMAINED APPROX 2 MINS FOR THE NECESSARY STABILIZATION TIME ON THE PW4000 ENGS. TWR CLRED US INTO POS AND HOLD ON RWY 10R AND WE ACKNOWLEDGED AND ADVISED ATC OF THE ADDITIONAL TIME WE WOULD REQUIRE PRIOR TO BEING ABLE TO ACCEPT A TKOF CLRNC. TWR'S RESPONSE WAS TO CANCEL CLRNC AND TO TAXI OVER TO RWY 10L VIA TXWY R. ANOTHER ACFT WAS PARKED ON TXWY S FACING SE AND NW OF TXWY R. WE COMPLIED WITH TWR'S INSTRUCTIONS AND UPON ARR AT RWY 10L, WERE INSTRUCTED TO TAXI INTO POS AND HOLD. I ASKED THE FO WHETHER WE WERE 'GOOD TO GO' ON RWY 10L FROM THE INTXN, 2 TIMES. THE REPLY WAS 'WE'RE GOOD ON RWY 10L,' AND 'WE'RE GOOD TO GO.' SUBSEQUENT CLRNC FOR TKOF WAS SOP AND UNEVENTFUL. TXWYS U AND R AT SFO'S S SIDE OF RWY 10L INTERSECT THE RWY VERY CLOSE TO THE SAME POINT. IN FACT, AN ARGUMENT COULD BE MADE THAT IF AN ACFT WAS INSTRUCTED TO TAXI INTO POS AND HOLD ON RWY 10L AT TXWY U AND DID SO, THE LINE-UP DISTANCE WOULD PUT THE ACFT GEOGRAPHICALLY VERY CLOSE AND ADJACENT TO TXWY R. THE POINT, HOWEVER, IS THIS: ONCE AIRBORNE, I WENT BACK AND CHKED FOR MYSELF WHETHER IN FACT ENGINEERING NUMBERS EXISTED FOR AN INTXN DEP FROM TXWY R. I LEARNED THAT THEY DID NOT. THE SAFETY OF THE TKOF WAS NOT IN QUESTION AT THAT POINT. I KNEW THAT PLENTY OF RWY HAD BEEN AVAILABLE (GREATER THAN 10000 FT), TKOF DATA FOR RWY 10L TXWY U WAS AVAILABLE, VFR WX CONDITIONS EXISTED, A RELATIVELY LIGHT ACFT WT, AND PARALLEL RWYS IN VERY CLOSE PROX TO ONE ANOTHER, THE TKOF DATA OF WHICH HAD BEEN JUST THOROUGHLY REVIEWED. WHAT DID TROUBLE ME WAS MY FAILURE TO CONVEY TO THE FO A CLR AND ACCURATE INQUIRY REGARDING THE 'LEGALITY' OF THAT SPECIFIC TKOF FROM RWY 10L AT TXWY R INTXN. NOTHING ON THAT DAY WOULD HAVE SUGGESTED WE WERE IN A RWY OR PERFORMANCE LIMITED SIT OR OTHER UNSAFE CONDITION, AND THEREFORE NO OBVIOUS 'RED FLAGS' WERE WAVING BEFORE MY EYES. I DID EVEN RECOGNIZE AND ACKNOWLEDGE THE NEED TO CHK FOR ENGINEERING NUMBERS FOR A DEP FROM THAT INTXN. THE BREAKDOWN OCCURRED IN COM. I HAVE SINCE RECAPPED THE SIT MANY TIMES AND HAVE RECOMMITTED MYSELF TO CLRER AND MORE ACCURATE COM SKILLS IN THE COCKPIT. THANKFULLY THIS WAS NOT A SIGNIFICANT EVENT. IT WAS, HOWEVER, A SIGNIFICANT AND VALUABLE LEARNING OPPORTUNITY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.